The Mind and the Brain (18 page)

When night fell, Ingrid Newkirk would stand outside, walkie-talkie in hand, playing lookout as Alex Pacheco slipped through the darkened labs of the Institute for Behavioral Research (IBR) in Silver Spring, Maryland, taking photos and scribbling in his notebook. Over the course of several weeks in late August and early September 1981, Pacheco surreptitiously escorted a number of sympathetic veterinarians and primatologists who supported animal rights through the facility, showing them the rusty cages encrusted with monkey feces, cages whose bent and broken wires poked up from the floor like stakes that threatened to impale the monkeys. He showed them the signs of rodent infestation and of insects. But mostly he showed them the animals: sixteen crab-eating macaques, all adult males, and one adult female rhesus. Among the seventeen, thirty-nine fingers had been gnawed off, and arms were covered with oozing, unbandaged lesions. Was this standard for a primate lab, Pacheco asked each expert, or was something wrong—very wrong—here?

What Pacheco didn’t know was that experiments conducted in this lab, grisly though they may have been, would overturn the dogma that the adult brain cannot be rewired.

In May 1981 Pacheco, then a twenty-two-year-old political science student at George Washington University, had applied for a job at the privately owned lab, four miles east of the nation’s premier biomedical campus, the National Institutes of Health (NIH), in Bethesda. He was trying to decide whether he wanted to make a career of biomedical research, Pacheco had told Edward Taub, IBR’s chief scientist. He was so fascinated by animal research, in fact, that he would gladly accept the unpaid, volunteer position that Taub offered him. As Taub told the
Washington Post
ten years later, he went home that night and raved to his wife, Mildred, an opera singer, about the “marvelous student” he had just met: “I told him there was no position, but he volunteered to work, out of pure interest,” Taub marveled. But Pacheco’s “pure interest” was not what Taub thought it was.

As a student at Ohio State University, Pacheco had burned with the passion of a true believer, and his true belief was that animals were needlessly subjected to cruelty, even torture. He had organized protests against the local farmers’ practice of castrating their pigs and cattle without anesthetic; angry ag majors threatened to do the same to Pacheco one night. Pacheco had hoped to study for the priesthood, but instead he moved east and joined Newkirk, nine years his senior and already an experienced animal rights leader, to form People for the Ethical Treatment of Animals (PETA). Newkirk, who had worked undercover at a Maryland animal shelter and exposed the appalling conditions there, suggested that Pacheco do the same in a lab. He therefore obtained a Department of Agriculture list of federally funded facilities where scientists used animals for biomedical research; of them, IBR was closest to his apartment in Takoma Park, Maryland. Exactly what IBR did, Pacheco had no idea. As it turned out, Taub would be conducting experiments on the very species of animal that Pacheco, who had divided his childhood between Mexico and the United States, once had as a pet. Pacheco’s Chi-Chi, like most of Taub’s animals, was a crab-eating macaque (that’s the species’ common
name, not its dietary preference) or cynomolgus monkey,
Macaca fascicularis
.

What we do here, Taub explained to Pacheco, is deafferent the monkeys’ limbs. Afferent, or sensory, input from the body enters the spinal cord over the dorsal (back) routes to the spinal nerves. If nerves innervating some part of the body—an arm, for instance—are cut where they enter the cord, then that part of the body loses all sensation. The animal no longer feels its arm, or leg, or whatever limb has been deafferented. Taub was particularly interested in depriving single limbs, usually one arm, of afferent input and observing how that affected the animal’s use of the arm. Because only the sensory nerve from the arm, and not the motor nerve, would be severed, it seemed logical that the adult animal would be able to continue using the arm. But a leading theory in behavioral psychology held that sensory input was crucial to motor function. This is what Taub planned to test. To do so, he performed the surgery on nine of his sixteen crab-eating macaques: Billy, one of the monkeys, had the sensory nerves to both arms severed, and the eight others had the nerve to a single arm severed. Seven other macaques, and Sarah, the lone rhesus and the only female, served as the controls. Taub had just received an $180,000 grant from NIH to continue this investigation.

Taub found that the deafferented monkeys, consistent with a long-standing theory in neurophysiology, did not naturally use the deafferented limb; without feeling, the arm seemed to hang like a dead weight, and the monkeys in many cases appeared to forget it was even there. So Taub tested whether the monkeys’ reluctance, or refusal, to use the impaired limb could be overcome. Using a straitjacket to restrain the good arm, which the monkeys favored for tasks from ambulating to eating, he left them no option (if they wanted to get around and to eat) but to use the damaged one. He strapped the monkeys into chairs and, if they failed to flex the “affected arm,” as Taub delicately called the seemingly useless one,
administered a strong electric shock to them. Subjected to these massively stressful “negative reinforcements,” the animals did indeed move the senseless limb. Eventually, Taub would examine the monkeys’ nerves to see whether they had undergone any change—to see whether, for instance, any had grown back as a result of the animals’ being forced to use the deafferented arm. That would mean killing the monkeys. But if the experiments showed what Taub expected and hoped, the results just might lead to new treatments for victims of stroke and brain trauma.

Pacheco wasn’t interested in looking that far ahead. All he saw was what lay before him, and what he saw sickened him. The animals were housed in rusty old cages whose filth was surprising, for a lab; Pacheco reeked every night, recalls Newkirk, with whom he was living. Inspectors from the U.S. Department of Agriculture, which enforces lab animal laws, visited Taub’s lab during Pacheco’s time there; they reported no serious deficiencies. Given that, Pacheco wasn’t sure what, exactly, would qualify as a deficiency (apparently not the monkey corpse he had found floating in a vat of formaldehyde). The living ones might well have envied the dead: they would spin around constantly, bouncing off the cage walls, masturbating compulsively—as macaques caged alone are wont to do. But these animals had an additional habit that horrified Pacheco. They chewed their deafferented limbs raw and gnawed off their fingers. From the shoulder down, of course, the affected limbs had no feeling.

Pacheco began documenting what he saw, shooting photographs and taking notes. When he told Taub he wanted to work nights and weekends, a grateful (and unsuspecting) Taub gave him the keys to the lab. That’s how Pacheco came to be inside on those late summer nights in 1981, with Newkirk acting as lookout, each equipped with a walkie-talkie they had bought at a toy store. From August 24 to September 4, Pacheco sneaked five veterinarians and primatologists into the lab. Animal rights sympathizers, they provided
the PETA pair with affidavits testifying to the conditions of the animals and of the lab. The next month, Newkirk and Pacheco took the affidavits and photos to the local police department.

The Montgomery County, Maryland, police raided the Institute for Behavioral Research on September 11, seizing all seventeen monkeys: Adidas, Allen, Augustus, Big Boy, Billy, Brooks, Charlie, Chester, Domitian, Hard Times, Hayden, Montaigne, Nero, Paul, Sarah, Sisyphus, and Titus. (Some of the monkeys had been named by Taub’s students and assistants; the classical names came from Taub himself, who had long felt that some of the Roman emperors had not received their due from historians.) Taub had not been working that Friday, but when he rushed to the lab after an assistant phoned to tell him about the raid, he couldn’t believe what was happening. He told a reporter, “I’m surprised, distressed and shocked by this. There is no pain in these experiments. We surgically abolish pain.” Although neither Taub’s experimental methods, nor the conditions in his lab, were grossly out of line with then-common practice, on September 28 the prosecutor charged Taub with seventeen counts of animal cruelty. The saga of the Silver Spring monkeys—one that would drag through the courts for ten years, embroil powerful congressmen in the fate of seventeen monkeys, and do more than any other single incident to launch the animal rights movement in the United States—had begun.

Edward Taub has mellowed in his later years. Yet you can still detect, in the self-assurance, shadows of the arrogance that once so infuriated other researchers that their faces would turn crimson and their lips would be reduced to sputtering as, in one case that he delights in telling, they lost their adopted English and fell back on their native Finnish to denounce him at a scientific meeting. And you can still detect the figurative thumbing-of-the-nose at scientific paradigms that provoked his bosses, even when they grudgingly granted him permission to carry out studies that threatened (or promised?) to topple those paradigms, to demand that he allow
“observers” in, to keep an eye on him. And you can still detect the almost naïve view that scientific truth would vanquish ignorance and sentimentality. But although Taub had no trouble questioning the received wisdom in neuroscience and harbored no doubts that he, an outsider from the lowly field of behavioral psychology, had the right to question neuroscience “facts” dating back a century, it never dawned on him that using what were then (regrettably) not-uncommon laboratory procedures would earn him a singular distinction: the first scientist ever charged with animal cruelty.

Taub was born in New York City in 1931. After receiving his undergraduate degree in psychology from Brooklyn College in 1953, he began working toward his doctorate at Columbia University. As a grad student, he worked with monkeys at the Jewish Chronic Disease Hospital in Brooklyn. It was there that he was introduced to the experimental procedure that would first break him and then make him: limb deafferentation. “This was my advantage: that I was a psychologist who had never studied neuroscience except on my own,” he says. He therefore had not been inculcated with the conventional wisdoms of the field, one of the most important of which dated back to classical experiments by the British neurophysiologist Sir Charles Sherrington.

In 1895 Sherrington, working with F.W. Mott, reported the results of a now-classic experiment in which he deafferented a single upper forelimb or lower limb of rhesus monkeys. Sherrington pioneered deafferentation experiments, painstakingly severing the sensory nerves but leaving motor nerves intact, much as Taub would some sixty years later. Sherrington and Mott sought to investigate whether the animals would continue to use the deafferented limb. They found, instead, that after they cut the sensory nerves, the monkeys stopped using the affected limb. The animals were completely unable voluntarily to grasp, to support their weight, or to ambulate with the deafferented limb. The “volitional power,” as Sherrington and Mott called it, “for grasping with the hand etc. had been absolutely abolished.” Even when Sherrington restrained a
monkey’s remaining good arm, deferred feeding time, and then put a morsel within reach, the monkey did not use its deafferented arm to reach for the food. The only movements it seemed willfully capable of were crude rapid jerks, which were induced in the monkeys by causing them to “struggle,” as when they tried to free themselves while being held awkwardly. Sherrington attributed these motor actions to reflex effects triggered by movements in intact parts of the body. Since the motor nerves were still intact, why should somatosensory deafferentation abolish the ability of the monkey to move that arm? This was even more perplexing given that stimulating the motor area of the cerebral cortex elicited totally normal movement of the affected limb. Reflecting on the 1895 results in 1931, Sherrington said this served as “a caveat against accepting the movement excited electrically at the motor cortex as any close homologue of a willed one.”

What the disconnection of sensory nerves did, Sherrington argued, was abolish a critical “influence of sensation upon voluntary movement,” thus interfering with a basic mechanism necessary for the expression of “volitional power.” As we will see, this observation somewhat overstated the case. In any event, working with Derek Denny-Brown, Sherrington replicated the deafferentation study, publishing virtually identical results in 1931, a year before he won the Nobel Prize.

Researchers as late as the mid-1950s continued to report that sensory deafferentation led to loss of motor ability. These results and others led Sherrington to conclude that the modulation of reflex pathways is the basis for purposive behavior: the brain’s motor cortex taps into preexisting reflex circuitry to carry out its commands. In other words, all voluntary behavior is built on integrated, hierarchical reflexes. An animal moves and the movement produces sensory feedback; feedback plus learning guide the next movement; this produces its own feedback, which, again in conjunction with learning, eventually produces, after countless itera
tions, purposive, sequential movement. This theory came to be called “Sherringtonian reflexology.”
*

“Reflexology was the dominant view in neuroscience, even more dominant than the idea that there is no plasticity in the adult brain,” recalls Taub.